Voltage Regulator for a New TV Set

[Matt Johnson]

My understanding of electricity is limited and could use the quick help.

I purchased an LED TV for my boat that uses 24 watts of power. I currently have it connected via an inverter, but the actual power the TV is getting from it's supply is 12v. I would like to cut out the inverter and supply it from my house 12v, but do not want the power fluctuation to be an issue. If I use a 12v voltage regulator like this (click here for the Ebay link), would this be all I need?

I'm thinking of cutting off the tv's power supply plug, soldering in this regulator, and wiring it directly to the D/C circuit breaker for Stereo/TV. Would this work?

I'm doing this for the convenience of not having to have the inverter on, but also to minimize the loss of electricity. After doing some research on the voltage regulator I listed, I see it's not a very efficient way of doing things. This would still be more efficient than the inverter correct?

Thanks,

Matt

[richardhula]

I assume you are using an inverter to supply the 110v AC needed by the TV.

Realistically this is the only voltage you can use to power your TV. Just because your inverter uses 12v DC to produce the 110v AC has no relevance to the needs of the TV.

For the record, I recently purchased a Samsung UA32B6000 LED TV & run it off a 400 watt simulated sine wave inverter. Being such its very efficient although I do get a slight hum from the TV itself (not the speakers) which would probably not be present with less efficient full sine wave one, but its not a problem for me.

[Matt Johnson]

Originally Posted by richardhula

I assume you are using an inverter to supply the 110v AC needed by the tv

The 12v inverter does convert to 120, but the TV also uses it's own power supply (wall wart) to down convert back to 12v. The tv actually uses 12v.

[richardhula]

Still not sure if I have this right. Are you intending to tap into the innards of the TV & inject 12 volts to power it or is it a dual voltage model that accepts 120v AC as well as 12v DC externally? Is there a spec sheet for it on the net?

Assuming it can be powered with 12 volts DC, connecting directly to your house battery bank shouldn't be a problem. Obviously the battery voltage will vary but the capacity & impedance of the bank will absorb any short term voltage fluctuations or spikes caused by charging sources, sudden loads etc.

[colemj]

Voltage regulation isn't free. That 12V regulator requires a 15V input to achieve 12V output, so it isn't going to be a good solution for you. And it is going to get hot enough to cause damage to things touching it without a heatsink and case.

A better solution is a DC/DC converter like this: Amazon.com: DC Car Charger Adapter for ASUS Eee PC 1000HE Netbook (Laptop NOT Included): Electronics

It will supply a steady 12V output from various input voltages considered "normal" for those experienced on a boat (12-15V). You can remove the converter from its cigarette lighter plug and put it in a small project box for wiring it inline, or just wire in a cigarette socket and insert it into that (makes it easier to remove the TV). Be sure to get the polarity correct when wiring the output to your TV's input. The polarity will be on the wall wart.

I hear people say all the time that they just "cut the cord and hook it to the DC system" for a variety of things like TV's and computers, but I don't think it is a good idea for a number of reasons. Particularly when you can easily and inexpensively regulate the supply.

This all assumes that your description of the TV is correct and it is powered by a wall wart with 120V AC in and 12V DC out (double check that).

Mark

[Matt Johnson]

Originally Posted by colemj

.

This all assumes that your description of the TV is correct and it is powered by a wall wart with 120V AC in and 12V DC out (double check that).

Mark

Mark,

That is perfect... I actually already have one of those for my Acer Netbook (forgot about it). This is much better solution than what I was thinking!

The wall wart does take 120 in and 12v out... I'll give it a shot wiring this weekend and report back.

[senormechanico]

Just plug it into the 12 volt socket and be done with it.
The internals of electronics are already regulated.
I repaired electronics for over 30 years (still do in another field) and there's nothing to worry about.

Just do it.

[Sunset]

I have been running an LCD TV that originally had a transformer (120v ac to 12v dc) by cutting the wires and hooking to the house power for 3+ years with no problems whatsoever.

[capn_billl]

Colemj has it right, yes; "most" electronic devices have a chip just like that one inside, but I wouldn't risk a $1000.00 TV or laptop on it. The cigarette lighter regulators are made by several companies, are cheap and easy to install, and, ... easy to replace if something goes wrong. I have one that regulates 12v to 9v for a monitor that uses 9v DC internally. I connected it to 12v direct for several hours with no harm, (except it got hot inside), but I wouldn't recommend it.

[Matt Johnson]

I ended-up following ColeMJ's advice and purchased this one: Car power supply charger, ASUS Eee PC 700 900 1000. The benefit I see with this item is that the cigarette plug is separate from the regulator and could be easily removed. The TV wasn't that expensive ($250), but the $14 investment is cheap insurance.


Thanks all!